This invention relates generally to radar displays and, more specifically, to vertical profile displays.
Analog radars can be configured to generate a vertical profile along any given radial. The operational difference between the standard weather radar and the vertical profile weather radar is the additional ability to scan the antenna up and down, generally about thirty degrees above and below the aircraft horizontal centerline to generate the vertical profile.
The vertical profile feature generates the vertical profile by direct means, i.e. scanning the vertical characteristics of the weather cell. The vertical profile augments the normal azimuth scan aiding the operator in developing a three-dimensioned mental image of the observed weather cell.
Vertical profile radars generally rely upon the skill of the operator interpreting the displayed return to discriminate between ground returns and weather. Ground returns generally appear to the operator or other viewer as a cross-section of a flashlight-like beam across the vertical profile. As the radar beam is scanned over the ground, the solid returns characterized by a mirror image above and below the ground level providing reflectivity equal to the beam width and power level. As the altitude and range increase, the ground returns will decay in much the same way as they increased from where the beam first intersected the ground. The problem is that where weather is present, it is often difficult to distinguish a line between ground and weather returns. One radar manufacturer, Bendix, makes the point in their owners manual for the model RDS 82VP: xe2x80x9cThe best time to begin using Vertical Profile is on a nice sunny day when the operator work load will allow time to experiment with the new feature . . . If you have completed the above operations on a sunny day as suggested, you have experienced the simple operation of Vertical Profile and observed a very unimpressive display of ground paint . . . The understanding of this very basic presentation is an important key in interpreting low level weather.xe2x80x9d
The principal problem is that vertical profile radar requires skill and judgment to properly interpret the low level weather. As the operator of an airplane will often have a number of instruments competing for the operator""s attention, requiring such skill and judgment in the course of operation of the airplane is not prudent. There exists an unmet need for vertical profile weather radar that suppresses returns from the ground.
The present invention includes a method and a system for suppressing or coloring the display of ground returns in a vertical profile radar.
In accordance with further aspects of the invention, a processor locates a ground level based either upon a database of vertical terrain elevation data or upon discerning a known characteristic ground return within a collated set of radar returns representing a vertical profile display.
In accordance with other aspects of the invention, once the ground level is located, the processor selectively suppresses or colors returns from radar range bins at the located ground level.
As will be readily appreciated from the foregoing summary, the invention provides a method for suppression of ground returns in a vertical profile radar display. The method includes receiving radar returns each comprising a plurality of range bins collated to a vertical profile radar display. The received range bins are analyzed to locate ground returns. A plurality of range bins are selected based upon the located ground returns. The radar returns are modified based upon the selected range bins.